1. Field of the Invention
The invention concerns a method and a device to detect information about the three-dimensional structure of a body cavity of a patient with an endoscopy capsule introduced into said body cavity. The invention also concerns an endoscopy capsule suitable for implementation of the method.
2. Description of the Prior Art
For optical examination of the inner surface of a body cavity (for example the gastrointestinal tract of a patient) it is basically known to introduce rigid or flexible endoscopes via body orifices, which endoscopes are mechanically controlled by the hand of the surgeon and enable a direct observation of the body cavity.
As an alternative to such manually controlled endoscopes, for example, from US 2006/0 209 185 A1, US 2005/0 124 858 A1 and DE 101 42 253 C1 it is known to introduce an endoscopy capsule into the body cavity, which endoscopy capsule acquires—with a video camera arranged on the front side of said endoscopy capsule—an image of the inner surface of the body cavity that is located in the field of view of the video camera without a fixed connection to the outside of the body cavity. The endoscopy capsule known from DE 101 42 253 C1 can, moreover, be freely maneuvered in the body cavity.
The spatial perception is severely limited by the monocular optics used in the known endoscopy capsule, and is based only on experimental values and the surgeon interprets brightness and color tone in the video image based on his or her anatomical knowledge and derives spatial information from these characteristics.
However, a 3D reconstruction of the body cavity is desirable both from a diagnostic standpoint and to control an endoscopy capsule that can be freely maneuvered in the body cavity.
In principle, a stereoscopic viewing would be possible if two video cameras could be used in the endoscopy capsule. Although an endoscopy device in which the endoscopy capsule includes two video cameras is known from DE 103 23 216 B3, these are arranged at opposite facing ends of the endoscopy capsule. Even in this known endoscopy capsule, in spite of the presence of two video cameras, a binocular viewing is not possible since their fields of view do not overlap in a manner that allows a stereoscopic view to be produced.
However, a stereoscopic image generation with two video cameras that are spaced apart from one another and whose image fields overlap is possible only to a limited extent due to the small structural dimensions of an endoscopy capsule.